CVE-2026-43912

What it is

Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to 1.35.5, Vaultwarden does not enforce that a groups_users.users_organizations_uuid entry belongs to the same organization as groups.groups_uuid, or a collections_groups.collections_uuid entry belongs to the same organization as collections_groups.groups_uuid. Multiple organization group-management endpoints accept arbitrary MembershipId and CollectionId values and persist them directly without verifying org consistency. This lets an attacker who is Admin in Organization A, and only a low-privileged member in Organization B bind their Org B membership UUID into an Org A group, then use that foreign group relationship to gain unauthorized access to Org B vault data. With an accessAll=true Org A group, the attacker can make /api/sync and /api/ciphers enumerate Org B ciphers. Once those unauthorized sync results reveal Org B collection IDs, the attacker can also bind those foreign collection IDs to the Org A group and turn the same flaw into write access over Org B items. This vulnerability is fixed in 1.35.5.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of data exposure, data tampering.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-11 23:20 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 18:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 8.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-05-11 23:20 UTC

Last modified

2026-10-26 18:10 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-285

Record status

Analyzed

Affected

• dani-garcia Vaultwarden < 1.35.5

Attack profile CVSS 3.1 · 8.7

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Is it in your code?

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